Planetary gear train of automatic transmission for vehicle

ABSTRACT

The present disclosure provides a planetary gear train of an automatic transmission including: input and output shaft, first to fifth planetary gear sets respectively having first to third, fourth to sixth, seventh to ninth, tenth to twelfth, and thirteenth to fifteenth rotational elements, a first shaft connected with the second and fifth rotational elements and the input shaft, a second shaft connected with the fourteenth rotational element and the output shaft, a third shaft connected with the eighth and thirteenth rotational elements, a fourth shaft connected with the eleventh and the fifteenth rotational elements, a fifth shaft connected with the sixth rotational element, a sixth shaft connected with the ninth and twelfth rotational elements, a seventh shaft connected with the tenth rotational element, an eighth shaft connected with the first and seventh rotational elements, and a ninth shaft connected with the third and fourth rotational elements.

CROSS-REFERENCE TO RELATED APPLICATION

This present application claims priority to and the benefit of KoreanPatent Application No. 10-2017-0058316 filed on May 10, 2017, which isincorporated herein by reference in its entirety.

FIELD

The present disclosure relates to an automatic transmission for avehicle.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

In the field of an automatic transmission, more multiplicity ofshift-stages is useful technology for enhancement of fuel consumptionand drivability of a vehicle.

Achieving more shift stages contributes to improve performance andefficiency of a vehicle in a trend so-called downsizing of an engine,and more linearity in step ratios of the shift-stages enhancesdrivability of the vehicle by improving uniformity of accelerationbefore and after a shifting, etc.

In order to achieve more shift-stages for an automatic transmission, thenumber of parts is typically increased, which may negatively affectinstallability, production cost, weight and/or power flow efficiency.

Therefore, in order to enhance fuel consumption of an automatictransmission having more shift-stages, it is desired that betterefficiency is derived with less number of parts.

In this asepct, an eight-speed automatic transmission has beenintroduced recently and a planetary gear train for an automatictransmission enabling more shift-stages has been investigated.

A recent eight-speed automatic transmission typically shows a gear ratiospan, which is a significant factor for securing linearity of stepratios, in a level of 6.5 to 7.5.

In addition, we have discovered that an eight-speed automatictransmission may become inferior in respect of linearity of step ratiosof shift-stages even if the gear ratio span may rise a level above 9.0.

SUMMARY

The present disclosure provides a planetary gear train realizing tenforward speeds and at least one reverse speed by utilizing fiveplanetary gear sets and six engagement elements, thereby reducing a dragloss and improving power delivery efficiency and fuel consumption.

Also, the present disclosure employs a torque-in-parallel scheme to anoutput side planetary gear set, thereby reducing torque loads ofengagement elements and improving torque delivery efficiency anddurability.

In addition, the present disclosure improves flexibility of output gearratio, thereby improving linearity of step ratios of shift-stages.

One form of planetary gear train of an automatic transmission for avehicle may include: an input shaft, an output shaft, first to fifthplanetary gear sets respectively having first to third, fourth to sixth,seventh to ninth, tenth to twelfth, and thirteenth to fifteenthrotational elements, a first shaft fixedly connected with the second andfifth rotational elements, and the input shaft, a second shaft fixedlyconnected with the fourteenth rotational element and the output shaft, athird shaft fixedly connected with the eighth and thirteenth rotationalelements, a fourth shaft fixedly connected with the eleventh and thefifteenth rotational elements, a fifth shaft fixedly connected with thesixth rotational element, a sixth shaft fixedly connected with the ninthand twelfth rotational elements, a seventh shaft fixedly connected withthe tenth rotational element, an eighth shaft fixedly connected with thefirst and seventh rotational elements, and a ninth shaft fixedlyconnected with the third and fourth rotational elements.

The planetary gear train may further include six engagement elements,each of which configured to selectively connect a corresponding pairamong the first to ninth shaft, the input shaft, the output shaft, andthe transmission housing, wherein three engagement elements areconfigured to operate for respective shift-stages.

The six engagement element may include three clutches and three brakes.

The six engagement elements may include: a first clutch arranged betweenthe first shaft and the seventh shaft, a second clutch arranged betweenthe third shaft and the fifth shaft, a third clutch arranged between thefourth shaft and the fifth shaft, a first brake arranged between theeighth shaft and the transmission housing, a second brake arrangedbetween the ninth shaft and the transmission housing, and a third brakearranged between the third shaft and the transmission housing.

The first, second, and third rotational elements may be a first sungear, a first planet carrier, and a first ring gear of the firstplanetary gear set. The fourth, fifth, and sixth rotational elements maybe a second sun gear, a second planet carrier, and a second ring gear ofthe second planetary gear set. The seventh, eighth, and ninth rotationalelements may be a third sun gear, a third planet carrier, and a thirdring gear of the third planetary gear set. The tenth, eleventh, andtwelfth rotational elements may be a fourth sun gear, a fourth planetcarrier, and a fourth ring gear of the fourth planetary gear set. Thethirteenth, fourteenth, and fifteenth rotational elements may be a fifthsun gear, a fifth planet carrier, and a fifth ring gear of the fifthplanetary gear set.

The first, second, third, fourth, and fifth planetary gear sets may bearranged in an order of the second, first, third, fourth, fifthplanetary gear sets from an engine side.

Another form of the present disclosure utilizes five planetary gear setsoperated by six engagement elements, and thereby achieves the tenforward speeds and at least one reverse speed.

In addition, the gear ratio span of at least 9.5 may be achieved so asto enhance an engine driving efficiency, and a linearity of step ratiosof shift-stages may be also improved, thereby contributing to a betterdrivability of the vehicle.

While achieving ten forward speeds and at least one reverse speed,engagement element operation is minimized so as to reduce a drag loss,thereby improving power delivery efficiency and fuel efficiency.

A torque-in-parallel scheme is applied to an output side planetary gearset, and thus the torque loads may be evenly distributed to planetarygear sets and engagement elements, thereby improving torque deliveryefficiency and durability.

By using five planetary gear sets to realize ten forward speeds and atleast one reverse speed, wider range of output gear ratios may beachieved, thereby improving linearity in step ratios of shift-stages.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a planetary gear train; and

FIG. 2 is an operational chart of engagement elements for respectiveshift-stages applied to a planetary gear train.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

In the following description, dividing names of components into first,second and the like is to divide the names because the names of thecomponents are the same as each other and an order thereof is notparticularly limited. Further, as used herein, description of elementsbeing “fixedly” connected or interconnected includes elements that arealways connected directly or indirectly, such that the fixedly connectedelements always rotate at a same speed.

FIG. 1 is a schematic diagram of a planetary gear train according to anexemplary form of the present disclosure.

Referring to FIG. 1, a planetary gear train according to an exemplaryform of the present disclosure includes first, second, third, fourth,and fifth planetary gear sets PG1, PG2, PG3, PG4, and PG5 arranged on asame axis, an input shaft IS, an output shaft OS, nine shafts TM1 to TM9interconnecting rotational elements of the first, second, third, fourth,and fifth planetary gear sets PG1, PG2, PG3, PG4, and PG5, engagementelements of three clutches C1 to C3 and three brakes B1 to B3, and atransmission housing H.

A torque of an engine input to the input shaft IS is shifted bycooperative operation of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, and a shifted torque isoutput through the output shaft OS.

In some forms of the present disclosure, the planetary gear sets arearranged in the order of the second, first, third, fourth, and fifthplanetary gear sets PG2, PG1, PG3, PG4, and PG5, from an engine side.

The input shaft IS is an input member and the torque from a crankshaftof an engine is input into the input shaft IS, after beingtorque-converted through a torque converter.

The output shaft OS is an output member arranged on the same axis withthe input shaft IS, and transmits the shifted torque to a drive shaftthrough a differential apparatus.

The first planetary gear set PG1 is a single pinion planetary gear set,and includes a first sun gear S1, a first planet carrier PC1 rotatablysupporting a plurality of first pinion gears P1 externally gear-meshedwith the first sun gear S1, and a first ring gear R1 internallygear-meshed with the plurality of first pinion gears P1. The first sungear S1 acts as a first rotational element N1, the first planet carrierPC1 acts as a second rotational element N2, and the first ring gear R1acts as a third rotational element N3.

The second planetary gear set PG2 is a single pinion planetary gear set,and includes a second sun gear S2, a second planet carrier PC2 rotatablysupporting a plurality of second pinion gears P2 externally gear-meshedwith the second sun gear S2, and a second ring gear R2 internallygear-meshed with the plurality of second pinion gears P2. The second sungear S2 acts as a fourth rotational element N4, the second planetcarrier PC2 acts as a fifth rotational element N5, and the second ringgear R2 acts as a sixth rotational element N6.

The third planetary gear set PG3 is a single pinion planetary gear set,and includes a third sun gear S3, a third planet carrier PC3 rotatablysupporting a plurality of third pinion gears P3 externally gear-meshedwith the third sun gear S3, and a third ring gear R3 internallygear-meshed with the plurality of third pinion gears P3. The third sungear S3 acts as a seventh rotational element N7, the third planetcarrier PC3 acts as a eighth rotational element N8, and the third ringgear R3 acts as a ninth rotational element N9.

The fourth planetary gear set PG4 is a single pinion planetary gear set,and includes a fourth sun gear S4, a fourth planet carrier PC4 rotatablysupporting a plurality of fourth pinion gears P4 externally gear-meshedwith the fourth sun gear S4, and a fourth ring gear R4 internallygear-meshed with the plurality of fourth pinion gears P4. The fourth sungear S4 acts as a tenth rotational element N10, the fourth planetcarrier PC4 acts as a eleventh rotational element N11, and the fourthring gear R4 acts as a twelfth rotational element N12.

The fifth planetary gear set PG5 is a single pinion planetary gear set,and includes a fifth sun gear S5, a fifth planet carrier PC5 rotatablysupporting a plurality of fifth pinion gears P5 externally gear-meshedwith the fifth sun gear S5, and a fifth ring gear R5 internallygear-meshed with the plurality of fifth pinion gears P5. The fifth sungear S5 acts as a thirteenth rotational element N13, the fifth planetcarrier PC5 acts as a fourteenth rotational element N14, and the fifthring gear R5 acts as a fifteenth rotational element N15.

In the arrangement of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, the first rotationalelement N1 and the seventh rotational element N7 are fixedlyinterconnected, the second rotational element N2 and the fifthrotational element N5 are fixedly interconnected, the third rotationalelement N3 and the fourth rotational element N4 are fixedlyinterconnected, the eighth rotational element N8 and the thirteenthrotational element N13 are fixedly interconnected, the ninth rotationalelement N9 and the twelfth rotational element N12 are fixedlyinterconnected, the eleventh rotational element N11 and the fifteenthrotational element N15 are fixedly interconnected, and nine shafts TM1to TM9 are formed.

The nine shafts TM1 to TM9 are hereinafter described in detail.

Each of the ten shafts TM1 to TM9 may be a rotational member thatfixedly interconnects the input and output shafts and rotationalelements of the planetary gear sets PG1, PG2, PG3, PG4, and PG5, or maybe a rotational member that selectively interconnects a rotationalelement to the transmission housing H, or may be a fixed member fixed tothe transmission housing H.

The first shaft TM1 is connected with the second rotational element N2(first planet carrier PC1) and the fifth rotational element N5 (secondplanet carrier PC2), and fixedly connected with the input shaft IS,thereby always acting as an input element.

The second shaft TM2 is connected with the fourteenth rotational elementN14 (fifth planet carrier PC5), and fixedly connected with the outputshaft OS, thereby always acting as an output element.

The third shaft TM3 is connected with the eighth rotational element N8(third planet carrier PC3) and the thirteenth rotational element N13(fifth sun gear S5).

The fourth shaft TM4 is connected with the eleventh rotational elementN11 (fourth planet carrier PC4) and the fifteenth rotational element N15(fifth ring gear R5).

The fifth shaft TM5 is connected with sixth rotational element N6(second ring gear R2).

The sixth shaft TM6 is connected with the ninth rotational element N9(third ring gear R3) and the twelfth rotational element N12 (fourth ringgear R4).

The seventh shaft TM7 is connected with tenth rotational element N10(fourth sun gear S4).

The eighth shaft TM8 is connected with the first rotational element N1(first sun gear S1) and the seventh rotational element N7 (third sungear S3).

The ninth shaft TM9 is connected with the third rotational element N3(first ring gear R1) and the fourth rotational element N4 (second sungear S2).

The first shaft TM1 is selectively connected with the seventh shaft TM7,and the third shaft TM3 and the fourth shaft TM4 are selectivelyconnected with the fifth shaft TM5.

In addition, the third shaft TM3, the eighth shaft TM8, and ninth shaftTM9 are selectively connected with the transmission housing H, therebyselectively acting as a fixed element.

The three engagement elements of clutches C1, C2, and C3 are arrangedbetween the nine shafts TM1 to TM9, the input shaft IS, and the outputshaft OS, so as to form selective connections.

The three engagement elements of brakes B1, B2, and B3 are arrangedbetween the nine shafts TM1 to TM9 and the transmission housing H, so asto form selective connections.

The six engagement element of the three clutches C1 to C3 and the threebrakes B1 to B3 are arranged as follows.

The first clutch C1 is arranged between the first shaft TM1 and theseventh shaft TM7, and selectively connects the first shaft TM1 and theseventh shaft TM7, thereby controlling power delivery therebetween.

The second clutch C2 is arranged between the third shaft TM3 and thefifth shaft TM5, and selectively connects the third shaft TM3 and thefifth shaft TM5, thereby controlling power delivery therebetween.

The third clutch C3 is arranged between the fourth shaft TM4 and thefifth shaft TM5, and selectively connects the fourth shaft TM4 and thefifth shaft TM5, thereby controlling power delivery therebetween.

The first brake B1 is arranged between the eighth shaft TM8 and thetransmission housing H, and selectively connects the eighth shaft TM8 tothe transmission housing H.

The second brake B2 is arranged between the ninth shaft TM9 and thetransmission housing H, and selectively connects the ninth shaft TM9 tothe transmission housing H.

The third brake B3 is arranged between the third shaft TM3 and thetransmission housing H, and selectively connects the third shaft TM3 tothe transmission housing H.

The engagement elements of the first, second, and third clutches C1, C2,and C3 and the first, second, and third brakes B1, B2, and B3 may berealized as multi-plate hydraulic pressure friction devices that arefrictionally engaged by hydraulic pressure, however, it should not beunderstood to be limited thereto, since various other configuration thatare electrically controllable may be available.

FIG. 2 is an operational chart of engagement elements for respectiveshift-stages applied to a planetary gear train in some forms of thepresent disclosure.

Referring to FIG. 2, a planetary gear train in some forms of the presentdisclosure realizes ten forward speeds and at least one reverse speed byoperating three engagements among the first, second, and third clutchesC1, C2, and C3 and first, second, third brake B1, B2, and B3.

In the forward first speed D1, the first clutch C1 and the first andthird brakes B1 and B3 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1. In this state, the input torqueis input to the first shaft TM1.

In addition, the eighth and third shafts TM8 and TM3 respectively act asfixed elements by the operation of the first and third brakes B1 and B3,thereby realizing the forward first speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In the forward second speed D2, the first and third clutches C1 and C3and the third brake B3 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1, and the fourth shaft TM4 isinterconnected with the fifth shaft TM5 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, third shaft TM3 acts as a fixed element by the operation ofthe third brake B3, thereby realizing the forward second speed andoutputting a shifted torque to the output shaft OS connected with thesecond shaft TM2.

In the forward third speed D3, the third clutch C3 and the first andthird brakes B1 and B3 are simultaneously operated.

As a result, the fourth shaft TM4 is connected with the fifth shaft TM5by the operation of the third clutch C3. In this state, the input torqueis input to the first shaft TM1.

In addition, the eighth and third shafts TM8 and TM3 respectively act asfixed elements by the operation of the first and third brakes B1 and B3,thereby realizing the forward third speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In the forward fourth speed D4, the first and third clutches C1 and C3and the first brake B1 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1, and the fourth shaft TM4 isinterconnected with the fifth shaft TM5 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, eighth shaft TM8 acts as a fixed element by the operationof the first brake B1, thereby realizing the forward fourth speed andoutputting a shifted torque to the output shaft OS connected with thesecond shaft TM2.

In the forward fifth speed D5, the second and third clutches C2 and C3and the first brake B1 are simultaneously operated.

As a result, the third shaft TM3 is connected with the fifth shaft TM5by the operation of the second clutch C2, and the fourth shaft TM4 isinterconnected with the fifth shaft TM5 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, eighth shaft TM8 acts as a fixed element by the operationof the first brake B1, thereby realizing the forward fifth speed andoutputting a shifted torque to the output shaft OS connected with thesecond shaft TM2.

In the forward sixth speed D6, the first and second clutch C1 and C2 andthe first brake B1 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1, and the third shaft TM3 isinterconnected with the fifth shaft TM5 by the operation of the secondclutch C2. In this state, the input torque is input to the first shaftTM1.

In addition, eighth shaft TM8 acts as a fixed element by the operationof the first brake B1, thereby realizing the forward sixth speed andoutputting a shifted torque to the output shaft OS connected with thesecond shaft TM2.

In the forward seventh speed D7, the first, second, and third clutchesC1, C2, and C3 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1, third shaft TM3 is connectedwith the fifth shaft TM5 by the operation of the second clutch C2, andthe fourth shaft TM4 is interconnected with the fifth shaft TM5 by theoperation of the third clutch C3. In this state, the input torque isinput to the first shaft TM1.

Then, the first, second, third, fourth, and fifth planetary gear setsPG1, PG2, PG3, PG4, and PG5 integrally rotate, and the torque receivedat the first shaft TM1 is outputted as inputted, thereby realizing theforward seventh speed and outputting a shifted torque through the outputshaft OS connected with the second shaft TM2.

In the forward eighth speed D8, the first and second clutch C1 and C2and the second brake B2 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1, and the third shaft TM3 isinterconnected with the fifth shaft TM5 by the operation of the secondclutch C2. In this state, the input torque is input to the first shaftTM1.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the second brake B2, thereby realizing the forward eighthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward ninth speed D9, the second and third clutches C2 and C3and the second brake B2 are simultaneously operated.

As a result, the third shaft TM3 is connected with the fifth shaft TM5by the operation of the second clutch C2, and the fourth shaft TM4 isinterconnected with the fifth shaft TM5 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the second brake B2, thereby realizing the forward ninthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward tenth speed D10, the first and third clutches C1 and C3and the second brake B2 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1, and the fourth shaft TM4 isinterconnected with the fifth shaft TM5 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the second brake B2, thereby realizing the forward tenthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the reverse speed REV, the first clutch C1 and the second and thirdbrakes B2 and B3 are simultaneously operated.

As a result, the first shaft TM1 is connected with the seventh shaft TM7by the operation of the first clutch C1. In this state, the input torqueis input to the first shaft TM1.

In addition, the ninth and third shafts TM9 and TM3 respectively act asfixed elements by the operation of the second and third brakes B2 andB3, thereby realizing the reverse speed and outputting a shifted torqueto the output shaft OS connected with the second shaft TM2.

As described above, a planetary gear train in some forms of the presentdisclosure utilizes five planetary gear sets PG1, PG2, PG3, PG4, and PG5operated by six engagement elements of three clutches C1, C2, and C3 andthree brakes B1, B2, and B3, and thereby achieves the ten forward speedsand at least one reverse speed.

In addition, the gear ratio span of at least 9.5 may be achieved so asto enhance an engine driving efficiency, and a linearity of step ratiosof shift-stages may be improved as well, thereby contributing to abetter drivability of the vehicle.

While achieving ten forward speeds and at least one reverse speed,engagement element operation is minimized so as to reduce a drag loss,thereby improving power delivery efficiency and fuel efficiency.

A torque-in-parallel scheme is applied to an output side planetary gearset, and thus the torque loads may be evenly distributed to planetarygear sets and engagement elements, thereby improving torque deliveryefficiency and durability.

By using five planetary gear sets to realize ten forward speeds and atleast one reverse speed, wider range of output gear ratios may beachieved, thereby improving linearity in step ratios of shift-stages.

The description of the disclosure is merely exemplary in nature and,thus, variations that do not depart from the substance of the disclosureare intended to be within the scope of the disclosure. Such variationsare not to be regarded as a departure from the spirit and scope of thedisclosure.

<Description of symbols>

PG1, PG2, PG3, PG4, PG5: first, second, third, fourth, and fifthplanetary gear sets

S1,S2,S3,S4,S5: first, second, third, fourth, and fifth sun gears

PC1,PC2,PC3,PC4,PC5: first, second, third, fourth, and fifth planetcarriers

R1,R2,R3,R4,R5: first, second, third, fourth, and fifth ring gears

C1, C2, C3: first, second, and third clutches

B1, B2, B3: first, second, and third brakes

IS: input shaft

OS: output shaft

TM1, TM2, TM3, TM4, TMS, TM6, TM7, TM8, TM9: first, second, third,fourth,

fifth, sixth, seventh, eighth, and ninth shafts

What is claimed is:
 1. A planetary gear train of an automatictransmission for a vehicle, comprising: an input shaft configured toreceive an external torque; an output shaft configured to output ashifted torque; a first planetary gear set having first, second, andthird rotational elements; a second planetary gear set having fourth,fifth, and sixth rotational elements; a third planetary gear set havingseventh, eighth, and ninth rotational elements; a fourth planetary gearset having tenth, eleventh, and twelfth rotational elements; a fifthplanetary gear set having thirteenth, fourteenth, and fifteenthrotational elements; a first shaft fixedly connected with the secondrotational element, the fifth rotational element, and the input shaft; asecond shaft fixedly connected with the fourteenth rotational elementand the output shaft; a third shaft fixedly connected with the eighthrotational element and the thirteenth rotational element; a fourth shaftfixedly connected with the eleventh rotational element and the fifteenthrotational element; a fifth shaft fixedly connected with the sixthrotational element; a sixth shaft fixedly connected with the ninthrotational element and the twelfth rotational element; a seventh shaftfixedly connected with the tenth rotational element; an eighth shaftfixedly connected with the first rotational element and the seventhrotational element; and a ninth shaft fixedly connected with the thirdrotational element and the fourth rotational element.
 2. The planetarygear train of claim 1, further comprising: six engagement elements,wherein each engagement element is configured to selectively connect acorresponding pair among the first to ninth shaft, the input shaft, theoutput shaft, and the transmission housing, and wherein three engagementelements are configured to operate for respective shift-stages.
 3. Theplanetary gear train of claim 2, wherein the six engagement elementscomprise three clutches and three brakes.
 4. The planetary gear train ofclaim 2, wherein the six engagement elements comprise: a first clutcharranged between the first shaft and the seventh shaft; a second clutcharranged between the third shaft and the fifth shaft; a third clutcharranged between the fourth shaft and the fifth shaft; a first brakearranged between the eighth shaft and the transmission housing; a secondbrake arranged between the ninth shaft and the transmission housing; anda third brake arranged between the third shaft and the transmissionhousing.
 5. The planetary gear train of claim 1, wherein: the first,second, and third rotational elements of the first planetary gear setare respectively a first sun gear, a first planet carrier, and a firstring gear of the first planetary gear set; the fourth, fifth, and sixthrotational elements of the second planetary gear set are respectively asecond sun gear, a second planet carrier, and a second ring gear of thesecond planetary gear set; the seventh, eighth, and ninth rotationalelements of the third planetary gear set are respectively a third sungear, a third planet carrier, and a third ring gear of the thirdplanetary gear set; the tenth, eleventh, and twelfth rotational elementsof the fourth planetary gear set are respectively a fourth sun gear, afourth planet carrier, and a fourth ring gear of the fourth planetarygear set; and the thirteenth, fourteenth, and fifteenth rotationalelements of the fifth planetary gear set are respectively a fifth sungear, a fifth planet carrier, and a fifth ring gear of the fifthplanetary gear set.
 6. The planetary gear train of claim 1, wherein thefirst, second, third, fourth, and fifth planetary gear sets are arrangedin an order of the second, first, third, fourth, fifth planetary gearsets from an engine side.
 7. A planetary gear train of an automatictransmission for a vehicle, comprising: an input shaft configured toreceive an engine torque; an output shaft configured to output a shiftedtorque; a first planetary gear set having first, second, and thirdrotational elements; a second planetary gear set having fourth, fifth,and sixth rotational elements; a third planetary gear set havingseventh, eighth, and ninth rotational elements; a fourth planetary gearset having tenth, eleventh, and twelfth rotational elements; a fifthplanetary gear set having thirteenth, fourteenth, and fifteenthrotational elements; a first shaft fixedly connected with the secondrotational element, the fifth rotational element, and the input shaft; asecond shaft fixedly connected with the fourteenth rotational elementand the output shaft; a third shaft fixedly connected with the eighthrotational element and the thirteenth rotational element; a fourth shaftfixedly connected with the eleventh rotational element and the fifteenthrotational element; a fifth shaft fixedly connected with the sixthrotational element; a sixth shaft fixedly connected with the ninthrotational element and the twelfth rotational element; and a seventhshaft fixedly connected with the tenth rotational element; and aplurality of shafts comprising a rotation element of the first, second,and third planetary gear set that is not fixedly connected with any ofthe first to seventh shafts, wherein any shaft of the plurality ofshafts is configured to selectively connect to the transmission housing.8. The planetary gear train of claim 7, wherein the plurality of shaftscomprise: an eighth shaft fixedly connected with the first rotationalelement and the seventh rotational element; and a ninth shaft fixedlyconnected with the third rotational element and the fourth rotationalelement.
 9. The planetary gear train of claim 8, further comprising:three clutches, each of the three clutches configured to interconnectany two shafts selected from the nine shafts; and three brakes, each ofthe three brakes configured to selectively connect a corresponding shaftamong the nine shafts to the transmission housing, wherein thecorresponding shaft is not connected with the input shaft or the outputshaft.
 10. The planetary gear train of claim 9, wherein the threeclutches comprise: a first clutch arranged between the first shaft andthe seventh shaft; a second clutch arranged between the third shaft andthe fifth shaft; and a third clutch arranged between the fourth shaftand the fifth shaft, and wherein the three brakes comprise: a firstbrake arranged between the eighth shaft and the transmission housing; asecond brake arranged between the ninth shaft and the transmissionhousing; and a third brake arranged between the third shaft and thetransmission housing.
 11. The planetary gear train of claim 7, wherein:the first, second, and third rotational elements of the first planetarygear set are respectively a first sun gear, a first planet carrier, anda first ring gear of the first planetary gear set; the fourth, fifth,and sixth rotational elements of the second planetary gear set arerespectively a second sun gear, a second planet carrier, and a secondring gear of the second planetary gear set; the seventh, eighth, andninth rotational elements of the third planetary gear set arerespectively a third sun gear, a third planet carrier, and a third ringgear of the third planetary gear set; the tenth, eleventh, and twelfthrotational elements of the fourth planetary gear set are respectively afourth sun gear, a fourth planet carrier, and a fourth ring gear of thefourth planetary gear set; and the thirteenth, fourteenth, and fifteenthrotational elements of the fifth planetary gear set are respectively afifth sun gear, a fifth planet carrier, and a fifth ring gear of thefifth planetary gear set.
 12. The planetary gear train of claim 7,wherein the first, second, third, fourth, and fifth planetary gear setsare arranged in an order of the second, first, third, fourth, fifthplanetary gear set from an engine side.
 13. A planetary gear train of anautomatic transmission for a vehicle, comprising: an input shaftconfigured to receive an engine torque; an output shaft configured tooutput a shifted torque; a first planetary gear set having first,second, and third rotational elements; a second planetary gear sethaving fourth, fifth, and sixth rotational elements; a third planetarygear set having seventh, eighth, and ninth rotational elements; a fourthplanetary gear set having tenth, eleventh, and twelfth rotationalelements; a fifth planetary gear set having thirteenth, fourteenth, andfifteenth rotational elements; a first shaft fixedly connected with thesecond rotational element, the fifth rotational element, and the inputshaft; a second shaft fixedly connected with the fourteenth rotationalelement and the output shaft; a third shaft fixedly connected with theeighth rotational element and the thirteenth rotational element; afourth shaft fixedly connected with the eleventh rotational element andthe fifteenth rotational element; a fifth shaft fixedly connected withthe sixth rotational element; a sixth shaft fixedly connected with theninth rotational element and the twelfth rotational element; a seventhshaft fixedly connected with the tenth rotational element; and eighthand ninth shafts comprising a rotation element of the first, second, andthird planetary gear sets that is not fixedly connected with any of thefirst to seventh shafts, wherein the eighth and ninth shafts areconfigured to selectively connect to the transmission housing throughbrakes.
 14. The planetary gear train of claim 13, wherein: the first andseventh shafts, the third and fifth shafts, and the fourth and fifthshafts are configured to selectively interconnect one another throughclutches; the eighth shaft is fixedly connected with the firstrotational element and the seventh rotational element; and the ninthshaft is fixedly connected with the third rotational element and thefourth rotational element.
 15. The planetary gear train of claim 14,further comprising: a first clutch arranged between the first shaft andthe seventh shaft; a second clutch arranged between the third shaft andthe fifth shaft; a third clutch arranged between the fourth shaft andthe fifth shaft; a first brake arranged between the eighth shaft and thetransmission housing; a second brake arranged between the ninth shaftand the transmission housing; and a third brake arranged between thethird shaft and the transmission housing.
 16. The planetary gear trainof claim 13, wherein: the first, second, and third rotational elementsof the first planetary gear set are respectively a first sun gear, afirst planet carrier, and a first ring gear of the first planetary gearset; the fourth, fifth, and sixth rotational elements of the secondplanetary gear set are respectively a second sun gear, a second planetcarrier, and a second ring gear of the second planetary gear set; theseventh, eighth, and ninth rotational elements of the third planetarygear set are respectively a third sun gear, a third planet carrier, anda third ring gear of the third planetary gear set; the tenth, eleventh,and twelfth rotational elements of the fourth planetary gear set arerespectively a fourth sun gear, a fourth planet carrier, and a fourthring gear of the fourth planetary gear set; and the thirteenth,fourteenth, and fifteenth rotational elements of the fifth planetarygear set are respectively a fifth sun gear, a fifth planet carrier, anda fifth ring gear of the fifth planetary gear set.
 17. The planetarygear train of claim 13, wherein the first, second, third, fourth, andfifth planetary gear sets are arranged in an order of second, first,third, fourth, fifth planetary gear set from an engine side.